@b010985. Thanks for posting. I am a bit confused as to what you are talking about. You don’t need Easy Folder Listing module if you have Easy Folder Listing Pro plugin. However, if you want to use both together you can, since one is a module and the other a plugin. However, the plugin can do everything the module can do and much more. Also, you can use the plugin as a module if you put the plugin code in the “Custom HTML” module instance in the Module Manager.
Also, from the error you specify, for some reason the module was not uninstalled properly. What version of Joomla are you using?
If you uninstalled the module from the Extension Manager, but you still see the mod_easyfolderlisting folder in modules, then just access the site from your FTP client and delete it manually. If you didn’t uninstalled the module from the Extension Manager, but deleted the files, then you will have to remove its entry in the Joomla database extensions table. Googling “Module Install: Another module is already using directory:” will provide you will a lot of information from persons who have experienced this.
Hope this helps.